Criminalistics Exam 3

Physical integrity

Cardinal rule #1 (photography), provides permanent record, gives investigator opportunity to review evidence without handling it, gives jury opportunity to examine evidence it situates

Prevent defense

Closing off the crime scene from the public and only allowing essential personnel into the scene, while also securing a detailed chain of custody

Perimeter

include barricades and warning tape

Physical evidence

any object of material which a suspect leaves at or takes away from a crime scene, or which may otherwise be connected to a crime

Camera

a light-tight box with an opening in the front and a light-sensitive material in the back

Key/Legend

should be included in rought sketch of crime scene; translates symbols, letters and numbers

GIS

Geographic Information System; important field data and database capabilities

Legal integrity

Identification, marking, tagging, packaging, sealing, chain of custody

Chain of Custody

Basic principle: The number of persons who handle a given item of evidence from the time of the alleged offense until the ultimate disposition of the case; whoever handled the evidence when it was collected up until presented in court must be shown

Locard’s Exchange Principle (AKA Theory of Transfer)

A perpetrator can't commit a crime without leaving or taking something. “Someone always brings something to a crime scene, and someone always takes something away.”

Photography

“Phos” meaning light and “Graphos” meaning write; translated as meaning: To write or draw with light

Testimonial evidence

Evidence obtained by talking to people (victims, witnesses, suspect/actors)

Is it okay to move a piece of evidence before it is fully documented?

No

T/F. When investigating a crime scene, you always start in the middle of the scene, and then work your way to the boundaries of the scene

False; starting outside establishes a secure perimeter to protect evidence, and work inward to avoid destroying potential evidence

General steps of crime scene investigation

Initial notification, approaching the scene, securing the scene, preliminary survey, evaluate physical evidence, narrative description, photograph the scene, sketch/diagram the scene, search the scene, record/collect physical evidence, conduct final survey, release and/or secure the scene

Cardinal rule #1 of Crime Scene Investigation

Nothing gets moved or touched until it is photographed; once moved, it is impossible to restore to its original position/condition

Crime Scene

The physical location at which a crime has been committed and what crime(s) may have occurred

Where does a crime scene begin?

Where the actor turns intent into action

What is the first thing that should be done upon arriving at a crime scene?

Secure the scene

Be able to describe the General Rules of Crime Scene Investigation and what is the reasoning behind them?

Clear the largest area possible at first; the scene can always be narrowed down later; it may not be able to be expanded once the boundaries have been set; Continues through the escape of the suspect

Fixed location vs. Multiple location scene

Single location (extremely rare, indoor and outdoor scene); primary scene and secondary scene (both indoor and outdoor)

Which type of crime scene is the most common?

Multiple location scene

What materials should be available to you if you are trying to create a sketch of a crime scene?

Writing materials, ruler, steel tape, paper, clipboard or other drawing surface, drawing compass, magnetic compass

elements of a crime scene sketch that contribute to it being good and effective

Measurements, a scale, equipment, location, building, grounds, locality

Locality sketch

overall view of the scene and its environment

Grounds sketch

objective is to show the event in context with its general surroundings

building sketch

shows the interior of the building and the building in relation to adjacent buildings

Location sketch

total crime scene; include perimeter barricades and warning tapes

Rough sketch

includes location, date and time, incident number, authentication, weather and lighting, scale, compass orientation, identification of evidence, measurements, key or legend

Layout sketch

Rough sketch designed to provide an overview of the crime scene locality

Detailed sketch

Not drawn to scale; measurements for all evidence and other pertinent objects; provides blueprint for reconstruction

Blowup sketch

A detailed sketch of small areas inside a larger sketch

Exploded view

Folds walls down flat to illustrate interrelationships of blood spatter, bullet holes and trajectories

Rectangular coordinate method

utilizes the floor plan, a bird’s eye view can be drawn by using fixed points or a baseline

Transecting baseline method

utilizes the floor plan; measures to objects on each side of baseline

Cross projection method

shows three dimensional features; lays out walls on two-dimensional plane with floor

Elevation method

uses when a vertical plane is necessary; can be utilized in conjunction with the coordinate method to depict evidence on interior walls

Triangulation method

requires two- or three-person team; easily adapted to small or large scenes; use permanent fixed points

Polar coordinate method

establishment of baseline, measurement of angles in relation to baseline, surveyor skills required

purpose of crime scene sketching

Preserves an accurate “mind’s eye” picture for future reference, assists the court in visualizing the actual scene, indicates relative locations of objects and persons in the scene, clarifies photographs, notes, charts, and maps, and provides a permanent record of the fact

4 steps of crime scene photography

Overview photographs, medium range photographs, close-up photographs, and evidentiary photographs

the crime scene security Preserve and Protect Rule

prevent loss, prevent contamination, prevent alteration

why should anyone photograph a crime scene in the first place?

Document the original scene and related items, document the initial appearance of the physical evidence, and provide investigators and others with a permanent visual record of the scene, for use in hearings and court trials

What should a photographer be thinking about when photographing a crime scene?

-Go from general to specific

-From medium range, try to show the setting from at least two sides

-Keep perpendicular to the item or body

-Hands, document both sides; Feet, both top and bottom

-Also consider the mouth and nose areas

-Do NOT stage or try to replace moved items

-Try to have the photographs tell the story

-Most courts do not approve of Photoshop to edit/”fix” a photograph

-Every photograph taken at a scene is open to presentation in court, so don’t photograph anything that you wouldn’t want to testify to

What depth of field is ideal for Crime Scene Photography?

Maximum Depth of Field possible

Can photography be used to document any other things?

Should be used for all crash and crime scene photography

Why does the Chain of custody exist? Why does it matter?

It limits the number of people who come into contact with the evidence collected. The fewer the number of people who handle the evidence, the less the chances of loss, contamination, or alteration

Different types of lighting that can be implemented in photography

Natural (sun & overcast), artificial (flashlight, flash unit), Front lighting (evenly covered for good exposure), Side lighting (greater sense of depth, shape, and dimension), Back lighting (silhouettes and can fool a camera into incorrect exposures)

Basic components of a camera

Aperture, focal length of lens, depth of field, shutter speed, ISO, File format

Parameters

the crime scene begins where the actor turns intent into action; clear the largest area possible; the scene can always be made smaller; it may not be possible to enlarge it without contamination of evidence

Conduct the Search….

Link, Grid, Double Grid, Strip, Zone, Spiral/Circle, Wheel